for Ka = 4:4:5000
LT = [1 1020 20000 5000*Ka];
R = roots(LT);
%hold on
%plot (real(R(1)),imag(R(1)),'r*')
if Ka ~= 4080
hold on
plot (real(R(2)),imag(R(2)),'go')
hold on
plot (real(R(3)),imag(R(3)),'go')
end
if Ka==4080
hold on
plot (real(R(2)),imag(R(2)),'r*')
hold on
plot (real(R(3)),imag(R(3)),'b*')
end
end

